Reduction Pathways of Zofenopril Based on Experimental and Computational Approach and its Voltammetric Determination

Abstract

Electrochemical reduction behavior of Zofenopril (ZFN) was studied via experimental electrochemical methods and theoretical calculations performed at B3LYP/6-31+G (d)//AM1. Electrochemical studies based on one reversible and adsorption-controlled and two irreversible diffusion-controlled reduction peaks at -0.75 V, -1.3 V and -1.65 V, respectively on hanging mercury drop electrode (HMDE) versus Ag/AgCl, KCl (3.0 M) in Britton-Robinson buffer (BR) of pH 5.5. First peak (reversible one) was thought to be the reduction of carbonyl group activated by vicinal nitrogen and reoxidation to its original form, second reduction was supposed to be the reduction of other carbonyl and reduction of proton to hydrogen gas catalyzed by lone-pair electrons was proposed as third. Square-wave cathodic adsorptive stripping voltammetry has been developed and validated for quantification of ZFN in different samples. Linear working range was established as 0.03-1.05 mu M. Limit of determination (LOD) was calculated to be 0.01 mu M. Proposed method was successfully applied to assay the drug in tablets and human serum with good recoveries between 96.9 % and 101.4 % having relative standard deviation less than 10 %.